Field of the Invention
The present invention relates to a method and apparatus for transmitting a feedback signal, and more particularly, to a method and apparatus for transmitting a feedback signal of a terminal for receiving a plurality of beams having different directivity.
Related Art
Recently, commercialization of a long term evolution (LTE) system which is a next-generation wireless communication system has been supported earnestly. After recognizing necessity for supporting not only a voice service but also a large amount service with high quality in response to a user's demand while ensuring activity of a user of a terminal, the LTE system tends to be more rapidly increased than before. The LTE system provides a low transmission delay, a high transfer rate, and an improved system capacity and coverage.
With an introduction of such a high-quality service, there is a rapidly growing demand on a wireless communication service. Above all, capacity of a communication system must be increased to actively cope with this situation. A method of newly discovering an available frequency band and a method of increasing efficiency for a limited resource may be considered as an alternative of increasing communication capacity in a wireless communication environment.
As the method of increasing the efficiency for the limited resource, a so-called multi-antenna transmission/reception technique is actively developed in recent years with a remarkable attention, in which a spatial region for resource utilization is additionally ensured by placing a plurality of antennas to a transceiver to obtain a diversity gain or in which transmission capacity is increased by transmitting data in parallel through the respective antennas.
In a multi-antenna system, beamforming and precoding may be used as a method of increasing a signal to noise ratio (SNR). The beamforming and the precoding are used to maximize the SNR through feedback information in a closed-loop system capable of using the feedback information in a transmitting end.
Meanwhile, although an increase in the number of antennas can lead to an increase in an average signal to interference plus noise ratio (SINR) of a cell-edge terminal by decreasing an interference occurrence probability, there is a problem in that the worst SINR cannot be improved occasionally.